Thermal Cycling Absorption Process (TCAP) is a well known hydrogen isotope separation technology. TCAP uses the isotopic effect of palladium absorption of hydrogen isotopes and different equilibrium pressures for isotope separation in the preference of tritium>deuterium>protium.
The conventional TCAP process uses a palladium deposited on kieselguhr (Pd/k) packed column with a plug flow revereser (PFR). The PFR is a larger diameter but shorter column packed with kieselguhr to enhance its plug flow characteristics. In operation, the Pd/k column temperature is cycled and the PFR is maintained at ambient temperature. During the cold phase of the cycle, gas flow is from the PFR to the Pd/k column and the heavier isotope is concentrated in the flow front. During the hot phase of the cycle, gas flows from the Pd/k column to the PFR and the concentration profile is mostly preserved due to the smaller isotopic effect of high temperature and the plug flow characteristic of the PFR.
The PFR in the above described process only provides a volume for the Pd/k column to regenerate. The passive PFR process does not provide for any separation of isotopes. While the TCAP using a passive PFR will produce a high purity heavy isotope product, it is not well suited to produce high purity light isotope within the raffinate stream at the same time.
Accordingly, there is room for variation and improvement within the art.